http://en.wikipedia.org/wiki/Federal_In ... ns_Act_tax
Some argue that since Social Security taxes are eventually returned to taxpayers, with interest, in the form of Social Security benefits, the regressiveness of the tax is effectively negated.[citation needed] That is, the taxpayer gets back what he or she put into the Social Security system. Others, including The Economist and the Congressional Budget Office, point out that the Social Security system as a whole is progressive in the lower income brackets; individuals with lower lifetime average wages receive a larger benefit (as both a percentage of their lifetime average wage income and a percentage of Social Security taxes paid) than do individuals with higher lifetime average wages.[22][23][24]